Anchor with hinged crown section



March 13, 1962 R. D. OGG 3,024,756

ANCHOR WITH HINGED CROWN SECTION Filed Dec. 21, 1960 2 Sheets-Sheet 1 INVEN TOR.

W BY

J ATTOPA/EKS March 13, 1962 R. D. 066 3,024,756

ANCHOR WITH HINGED CROWN SECTION Filed Dec. 21. 1960 2 Sheets-Sheet 2 Qllj ii -TIE; ,1 INVENTOR.'

A TTORWE K5 United States atent tice 3,024,756 ANCHOR WITH IIINGEI)CROWN SECTION Robert D. tigg, Portland, Maine, assignor to The EasternCompany, a corporation of Connecticut Filed Dec. 21, 1960. Ser. No.77,373 7 Claims. (Cl. 114-208) This invention relates to an improvedships anchor of the twin fluke type, particularly anchors constructed inaccordance with any one or more of Patents 2,249,546; 2,282,566;2,320,966; 2,567,390; 2,641,215 and 2,643,631.

The so called twin fluke anchor includes a shank and twin flukes,usually secured together as a unit and pivoted at one end of the shankwhereby both flakes engage the ground simultaneously. The anchor mayinclude a stock at either end of the shank although it is common topivot the shank on the stock so the latter is provided at the after endof the shank. Anchors of this type are known as having an extremely highholding power per pound of weight. For example, when such an anchor isengaged with a good sound bottom, it is not infrequently found that theanchor will hold several thousand times its own weight.

When such an anchor is cast overboard and is permitted to fall uponbottom, the pull provided by the attached anchor line or cable draws theanchor over the bottom. To ensure that the flukes engage bottompositively and without too much loss of time, it is usual to provide atthe after end of the anchor, a structure which facilitates movement ofthe flukes into operating position and ensures their rapid and positiveengagement with the bottom. This structure, usually termed a crown, hasincluded arrangements of both arcuate and plane surfaces extendingupwardly more or less directly from the plane of the Ilukes for aconsiderable distance above such plane. It is the function of thesesurfaces to ensure that the anchor engages bottom promptly and that theflukes are moved relative to the shank into their final operativeposition.

In Patent 2,641,215 the crown of such a twin fluke anchor is describedin considerable detail. It is said to be a particular advantage of thatanchor that it would engage a bottom promptly when drawn over the bottomand would not fioat." When an anchor floats, the flukes lie fiat on thebottom surface or are even inclined upwardly and do not fall intooperating position even though the anchor is drawn over the bottom forconsiderable distance. Floating occurs most frequently in a soft mudbottom. In fact, it is in a bottom of this characteristic that thegreatest ditficulty is encountered in securing the engagement of a twinfluke type anchor. This is because if such an anchor is designed tooperate satisfactorily on a hard sand bottom it generally will notengage promptly in a soft mud bottom. Many harbors and rivers throughoutthe world carry so much silt that effecting a proper anchorage is amatter of some dithcnlty. In many instances, the bottom will contain afluid mixture of silt and water of such low density that it isineffective in offering much more resistance to the movement of theanchor than water itself and, as a consequence. an anchor designed tofunction properly in hard sand is merely drawn through this fluid massineffectivcly.

The anchor of the present invention is particularly characterized by itsability to function satisfactorily in either type of bottom, that is, itpossesses the necessary characteristics for functioning satisfactorilyin a soft mud bottom as well as in a good hard sand bottom. To achievethis, the anchor possesses a crown structure including dual crown-platesmounted on each side of the anchor, one of each of the dual plates beingmovable with respect to the other whereby, upon engagement with a softbottom, the flukes are rotated into engaging position promptly andeffectively. If the anchor transverses the soft portion of the bottomand becomes engaged with hard sand, then one of the dual plates is movedinto a second position in which it provides the crown characteristicsnecessary to ensure proper engagement of the anchor in a hard sandbottom.

A further feature of the anchor of this invention is its ability to riditself of soft clinging mud by reason of the novel crown construction.

It is in general the broad object of the present invention to provide animproved twin fluke anchor construction in which a crown is providedhaving dual crownplates on each side thereof, one of each of the dualplates being movable with respect to the other whereby the crowncharacteristics initially provided are suited to the engagement of theanchor in a soft bottom, these characteristics changing automatically asthe anchor is moved into engagement with a firmer bottom.

The invention includes other objects and features of advantage, some ofwhich, together with the foregoing will appear hereinafter wherein thepresent preferred form of anchor is set forth.

In the drawings accompanying and forming a part hereof, FIGURE 1 is aside elevation showing an anchor constructed in accordance with thisinvention; the full lines show the anchor as it appears when engaged inhard bottom, while the dotted line shows the anchor as it appears freeof any bottom engagement or in a soft bottom.

FIGURE 2 is a top plan view of the anchor with the fiukes extended inthe same plane as the shank.

FIGURE 3 is an enlarged fragmentary view of the crown.

FIGURE 4 is an enlarged fragmentary view looking at the rear of theanchor and showing the construction of one of the dual crown-plates.

The anchor of the present invention includes a shank 6, a pair ofsubstantially like symmetrical flukes 7 and 8 disposed on opposite sidesof the shank. A stock 9 is extended between the fiukes 7 and 8 and thethree are joined together as by welding into a suitable unit, the shankbeing mounted between the flakes and pivotally supported on the stock 9.Each fluke includes a rib 11 extending along its inner edge adjacent tothe stock. Extending transversely of the plane of the flukes are spacerplates 14. the spacer plates extending above the plane of the fiukes ashort distance. Mounted upon the spacer plates on each side of theflukes are dual crown-plates 16 and 17 joined together by a hinge 18.Each crownplate 17 is fixed in position on the spacers and extendsforwardly over the fiukes at a small acute angle, e.g. 5 to 25, whilecrown-platcs I6 is urged by a spring 19 into a vertical position inwhich it stands upwardly in respect to the plane of the tlukes at anangle of approximately 80 to such plane. Any further movement of themovable plate 16 toward the flakes is limited by the construction of thehinge 18. The springs 19 are supported upon a pin 21 passed through thespacer plates. One end of the spring 19 bears against the back of aplate 16 while the other end of the spring is carried in a clip 22mounted on the side of a spaced plate.

Normally, the movable crown-plates each stand outwardly at an angle offrom about to about to the plane of the fiukes as is shown in FIGURE 1.Thus, in the normal position of engagement of the anchor in soft bottom,as is shown in dotted lines in FIGURE 1, both movable plates 16 standout at this angle to the plane of the flukes. The pressure applied bythe spring 19 is such that the plates are maintained in this positionunless and until the anchor comes into engagement with a bottom of suchconsistency that sutficient pressure is applied to move the platesagainst the bias of the springs into the full-line position in which theplates are shown in FIG- URE 1. Thus, the described anchor is such thatit functions effectively in either a soft or hard bottom, adjusting andsuiting itself to the characteristics of the bottom engaged.

As is set forth in Patent 2,641,215, in the preferred form of anchor thecrown-plates are preferably positioned so that from 20% to 50% of thearea of each dual crownplate is forward of the stock, the preferredvalue being 35% and the preferred range, 25% to 45%. Each dualcrown-plate is disposed fore and aft of the pivot and should preferablybe of an overall length equal to 19% of the shank length, the preferredrange being 15% to 23% and in any case the preferred overall lengthbetween 10% and 28% of the shank length; in the anchor shown in thedrawing, the shank length is the distance from the center of the cableattachment eye to the center of the stock.

Each fixed-crown plate 17 preferably slopes upwardly and away from theplane of the iiukes at a relatively small acute angle, preferably 14 andpreferably one within the range of 9 to 19 and in any case between 5 and24. Also, each dual crown plate must, for best results, be spaced fromthe center line of the pivot (measured in a direction substantiallynormal to the plane of the flukes) a distance equal to between 8% and10% of the shank length, the prefererd distance being in the range offrom 5% to 14%, and in any case, within the range of 3% to 16%; when thestock acts as the pivot mounting for the flukes, the stock center lineor longitudinal axis can be utilized in making this measurement.

In addition, I prefer that each plate 16 provide at least about 40% ofthe total area of the crown-plates and preferably from 50% to 75% ofsuch total area of the plates 16 and 17.

I claim:

1. An anchor of the twin fluke type having a shank with a forward and anafter end, a stock, a pair of flukes pivoted at the after end of theshank with the shank between the flukes, said fiukes having facesthereon substantially simultaneously engaging the ground in operativeposition; the improvement comprising a crown including a pair ofsubstantially flat crown-plates, each crown-plate being supported in theposition wherein said crown-plate is spaced from the plane of theflakes, each crown-plate includes a forward and after portion, the twoportions being hinged with respect to each other, the after portionbeing movable with respect to the flukes between a first position inwhich the movable plate stands at an angle of from about 70 to about 80to the plane of the flukes and a position in which said plate issubstantially parallel to the forward portion.

2. In an anchor of the twin fluke type having a shank with a forward andan after end, a stock, a pair of flukes pivoted at the after end of theshank with the shank between the flukes, said flukes having facesthereon substantially simultaneously engaging the ground in operativeposition; the improvement comprising a crown including a pair ofsubstantially flat crown-plates, each crown-plate being supported in aposition wherein said crown-plate is spaced from the plane of the fiukesa distance, measured outwardly from the center line of the stock and atsubstantially 90 to the plane of the flukes, of between about 3% andabout 16% of the shank length with each crown-plate sloping upwardly andrearwardly away from the plane of the flukes and being supported topermit bottom to flow freely between the fluke and the underside of thecrown-plate, each crown-plate having a width greater than about 5% ofthe shank length and a length of from about 10% to about 28% of thelength of the shank and being positioned with between about and about50% of its area forward of the pivot, each crown-plate including aforward and after portion, the two portions being hinged with respect toeach other, the after portion being movable with respect to the flukesbetween a first position in which the movable plate stands at an angleof from about 70 to about to the plane of the flakes and a position inwhich said plate is substantially parallel to the forward portion.

3. In an anchor of the twin fluke type having a shank with a forward andan after end, a stock, a pair of ilukes pivoted at the after end of theshank with the shank between the fiukes, said flukes having facesthereon substantially simultaneously engaging the ground in operativeposition; the improvement comprising a crown at the after end of theshank including a pair of substantially fiat crown-plates, and a thinfiat plate extending vertically to the plane of the fiukes and parallelto the shank and supporting each crown-plate in a position wherein eachcrown-plate is spaced from the plane of the fiukes a distance, measuredoutwardly from the center line of the stock and at substantially to theplane of the flukes, of between about 3% and about 16% of the shanklength and with the crown-plate sloping upwardly and rearwardly awayfrom the fiukes at an angle of from about 5 to about 24 to the plane ofthe fiukes, each crown-plate having a width of between about 5% to about17% of the shank length and a length of from about 10% to about 28% ofthe length of the shank, each crown-plate including a forward and afterportion, the two portions being hinged with respect to each other, theafter portion being movable with respect to the flukes between a firstposition in which the movable plate stands at an angle of from about 70to about 80 to the plane of the fiukes and a. position in which saidplate is substantially parallel to the forward portion.

4. In an anchor of the twin fluke type having a shank with a forward andafter end, a stock, a pair of flukes pivoted at the after end of theshank with the shank between the flukes and movable therebetween in aplane normal to the flukes, said flukes having faces thereonsubstantially simultaneously engaging the ground in operative position;a crown at the after end of the shank including a pair of substantiallyfiat crown-plates, each crown-plate being supported in a positionwherein said crown-plate is spaced from the plane of the fiukes adistance, measured outwardly from the center line of the stock and atsubstantially 90 to the plane of the fiukes of between about 3% andabout 16% of the shank length with the crown-plate sloping upwardly andrearwardly away from the fiukes at an angle of from about 5 to about 24to the plane of the flukes to permit bottom to flow freely between thefluke and the underside of the crown-plate, each crown-plate having alength of from about 10% to about 28% of the length of the shank and awidth greater than about 5% of the shank length and being positionedwith between about 20% and about 50% of its area forward of the pivot;the improvement comprising each crown-plate including a forward andafter portion, the two portions being hinged with respect to each other,the after portion being movable with respect to the flukes between afirst position in which the movable plate stands at an angle of fromabout 70 to about 80 to the plane of the fiukes and a position in whichsaid plate is substantially parallel to the forward portion.

5. In an anchor of the twin fluke type having a shank with a forward andan after end, a stock, a pair of flakes pivoted at the after end of theshank with the shank between the ilukes, said fiukes having facesthereon substantially simultaneously engaging the ground in operativeposition; a crown at the after end of the shank including a pair ofsubstantially flat crown-plates, each crown-plate being supportedcentrally of the fiukes and in a position wherein said crown-plate isspaced from the plane of the flakes a distance, measured outwardly fromthe center line of the stock and at substantially 90 to the plane of theflukes, of between about 3% and about 16% of the shank length with eachcrown-plate sloping upwardly and rearwardly away from the plane of theflukes, each crown-plate having a width greater than about of the shanklength and a length of from about to about 28% of the length of theshank; the improvement comprising each crown-plate including a forwardportion fixed relative to the flukes and an after portion hinged withrespect to said forward portion and to the fiukes.

6. An anchor of the twin fluke type having a shank with a forward and anafter end, a stock, a pair of fiukes pivoted at the after end of theshank with the shank between the flukes, said flukes having facesthereon substantially simultaneously engaging the ground in operativeposition; the improvement comprising a crown including a pair ofsubstantially flat crown-plates, each crown-plate being supported in theposition wherein said crown-plate is spaced from the plane of theflukes, each crown-plate includes a forward and after portion, the twoportions being hinged with respect to each other, the after portionbeing movable with respect to the fiukes between a first position inwhich the movable plate stands at an angle of from about 70 to about 80to the plane of the flukes and a position in which said plate issubstantially parallel to the forward portion providing at least about40% of the total area of the crown-plates.

7. In an anchor of the twin fluke type having a shank with a forward andan after end, a stock, a pair of fiukes pivoted at the after end of theshank with the shank between the flukes, said fiukes having facesthereon substantially simultaneously engaging the ground in operativeposition; a crown at the after end of the shank including a pair ofsubstantially flat crown-plates, each crown-plate being supportedcentrally of the fiukes and in a position wherein said crown-plate isspaced from the plane of the fiukes a distance, measured outwardly fromthe center line of the stock and at substantially 90 to the plane of theflukes, of between about 3% and about 16% of the shank length with eachcrown-plate sloping upwardly and rearwardly away from the plane of thefiukes, each crown-plate having a width greater than about 5% of theshank length and a length of from about 10% to about 28% of the lengthof the shank; the improvement comprising each crown-plate including aforward portion fixed relative to the fiukes and an after portion hingedwith respect to said forward portion and to the flukes, the forwardportion providing at least about of the total area of each crown-plate.

References Cited in the file of this patent UNITED STATES PATENTS2,576,390 Danforth Nov. 27, 1951 2,641,215 Danforth June 9, 19532,643,631 Danforth June 30, 1953

